Constructive and Destructive Forces — Reading Comprehension

Earth’s surface is constantly changing due to the action of powerful forces. These forces can be divided into two main types: constructive forces and destructive forces. Constructive forces, such as volcanic eruptions and tectonic uplift, build up Earth’s surface by creating new landforms. Destructive forces, like weathering and erosion, wear down and remove material from the surface. The interplay between these forces shapes the landscapes we see today and determines the size, shape, and features of mountains, valleys, deltas, and beaches.

How Constructive Forces Build Up Earth
Constructive forces are processes that add new material or elevate Earth’s surface. One major example is volcanic eruptions. When a volcano erupts, it releases lava, ash, and gases. The lava cools and hardens, forming new land, such as islands or mountains. The Hawaiian Islands, for instance, were built by repeated volcanic eruptions. Another constructive process is deposition. This occurs when rivers carry sediment and deposit it at their mouth, creating deltas like the Mississippi River Delta. Wind can also deposit sand to form dunes on beaches and in deserts. Tectonic uplift, caused by the movement of Earth’s plates, pushes entire regions upward, forming mountains and plateaus. Even living organisms can contribute: coral reefs are built by tiny animals called corals, which gradually accumulate their hard skeletons over thousands of years.

Destructive Forces That Wear Down Land
Destructive forces break apart and remove material from Earth’s surface. Weathering is the process that breaks rocks into smaller pieces through physical or chemical means. For example, water can seep into cracks in rocks, freeze, and expand, causing the rock to split. Chemical weathering can occur when rainwater, which is slightly acidic, dissolves certain minerals in rock. Erosion is the movement of broken-down material by wind, water, ice, or gravity. Rivers can carve valleys, glaciers can scrape out basins, and wind can blow away loose soil. Mass wasting is when gravity causes large amounts of rock or soil to move downhill in landslides or slumps. These destructive processes can happen rapidly, as in a landslide, or very slowly, as in the gradual wearing down of a mountain over millions of years.

Dynamic Balance: Landscapes Are Always Changing
The surface of Earth is shaped by both constructive and destructive forces working together. In some places, constructive forces dominate. For example, the Himalayas are still rising today due to tectonic uplift, even as weathering and erosion slowly wear them down. In other areas, destructive forces are stronger, reducing mountains to low, rolling hills. Landscapes with high relief, such as tall mountains and deep valleys, often show that uplift and building processes are faster than erosion. In contrast, flat plains and wide valleys often result from long-term erosion outpacing uplift. Scientists study rock layers, landforms, and rates of uplift or erosion to understand how these processes interact over time.

The balance between constructive and destructive forces is not always equal. Changes in climate, earthquakes, or human activities can tip the balance by accelerating erosion or increasing building processes. Understanding these forces helps us predict natural hazards, manage land use, and protect important ecosystems like beaches and deltas.

Interesting Fact:
Mount Everest, the highest mountain on Earth, is still rising by about 5 millimeters each year due to tectonic uplift, even as wind and water continue to erode its slopes.

Which of the following is a constructive force that forms new land?

What is the main role of destructive forces on Earth's surface?

Which process is responsible for creating a delta at the mouth of a river?

What is mass wasting?

In the passage, what does the word 'uplift' most nearly mean?

What does the word 'erosion' mean as used in the passage?

Why are the Himalayas still rising, according to the passage?

How might human activities affect the balance between constructive and destructive forces?

True or False: All mountains on Earth are only getting smaller due to erosion.

True or False: Beaches and deltas can be formed by the process of deposition.